package com.chinasofti.collection;

public class MyBinarySearchDemo {

    public static void main(String[] args) {
        int [] arr = {1,2,3,4,5,6,7,8,9,10};
        int number = 9;
        int i = binarySearch(arr,9);
        System.out.println("i = " + i);
    }
    private static int binarySearch(int[] arr,int number){
        int min = 0;
        int max = arr.length-1;
        while(min <= max){
            //计算出mid
            int mid = (min + max) >> 1;
            if(arr[mid] > number){
                //要查的元素在左边
                max = mid - 1;
            }else if(arr[mid] < number){
                min = mid + 1;
            }else{
                return mid;
            }
        }
        return -1;
    }
}
